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At least 127 records · Page 7Linked to original sources
USGS2014

Evaluation of juvenile salmonid behavior near a prototype weir box at Cowlitz Falls Dam, Washington, 2013

Collection of juvenile salmonids at Cowlitz Falls Dam is a critical part of the effort to restore salmon in the upper Cowlitz River because the majority of fish that are not collected at the dam pass downstream and enter a large reservoir where they become landlocked and lost to the anadromous fish population. However, the juvenile fish collection system at Cowlitz Falls Dam has failed to achieve annual collection goals since it first began operating in 1996. Since that time, numerous modifications to the fish collection system have been made and several prototype collection structures have been developed and tested, but these efforts have not substantially increased juvenile fish collection. Studies have shown that juvenile steelhead (Oncorhynchus mykiss), coho salmon (Oncorhynchus kisutch), and Chinook salmon (Oncorhynchus tshawytscha) tend to locate the collection entrances effectively, but many of these fish are not collected and eventually pass the dam through turbines or spillways. Tacoma Power developed a prototype weir box in 2009 to increase capture rates of juvenile salmonids at the collection entrances, and this device proved to be successful at retaining those fish that entered the weir. However, because of safety concerns at the dam, the weir box could not be deployed near a spillway gate where the prototype was tested, so the device was altered and re-deployed at a different location, where it was evaluated during 2013. The U.S. Geological Survey conducted an evaluation using radiotelemetry to monitor fish behavior near the weir box and collection flumes. The evaluation was conducted during April–June 2013. Juvenile steelhead and coho salmon (45 per species) were tagged with a radio transmitter and passive integrated transponder (PIT) tag, and released upstream of the dam. All tagged fish moved downstream and entered the forebay of Cowlitz Falls Dam. Median travel times from the release site to the forebay were 0.8 d for steelhead and 1.2 d for coho salmon. Most fish spent several days in the dam forebay; median forebay residence times were 4.4 d for juvenile steelhead and 5.7 d for juvenile coho salmon. A new radio transmitter model was used during the study period. The transmitter had low detection probabilities on underwater antennas located within the collection system, which prevented us from reporting performance metrics (discovery efficiency, entrance efficiency, retention efficiency) that are traditionally used to evaluate fish collection systems. Most tagged steelhead (98 percent) and coho salmon (84 percent) were detected near the weir box or collection flume entrances during the study period; 39 percent of tagged steelhead and 55 percent of tagged coho salmon were detected at both entrances. Sixty-three percent of the tagged steelhead that were detected at both entrances were first detected at the weir box, compared to 52 percent of the coho salmon. Twelve steelhead and 15 coho salmon detected inside the weir box eventually left the device and were collected in collection flumes or passed the dam. Overall, collection rates were relatively high during the study period. Sixty-five percent of the steelhead and 80 percent of the coho salmon were collected during the study, and most of the remaining fish passed the dam and entered the tailrace (24 percent of steelhead; 13 percent of coho salmon). The remaining 11 percent of steelhead and 7 percent of coho salmon did not pass the dam while their transmitters were operating. We were able to confirm collection of tagged fish at the fish facility using three approaches: (1) detection of radio transmitters in study fish; (2) detection of PIT-tags in study fish; (3) observation of study fish by staff at the fish facility. Data from all three methods were used to develop a multistate mark-recapture model that estimated detection probabilities for the various monitoring methods. These estimates then were used to describe the percent of tagged fish that were collected through the weir box and collection flumes. Detection probabilities of PIT-tag antennas in the collection flumes were 0.895 for juvenile steelhead and 0.881 for juvenile coho salmon, although radiotelemetry detection probabilities were 0.654 and 0.646 for the two species, respectively. The multistate model estimates showed that all steelhead and most coho salmon (94.5 percent) that were collected at the dam entered the collection system through the flumes rather than through the weir box. None of the tagged steelhead and only 5.5 percent of the tagged coho salmon were collected through the weir box. These data show that juvenile steelhead and coho salmon collection rates were much higher through the collection flumes than through the weir box. Low detection probabilities of tagged fish in the fish collection system resulted in uncertainty for some aspects of our evaluation. Missing detection records within the collection system for fish that were known to have been collected resulted in four tagged steelhead and seven tagged coho salmon being removed from the dataset, which was used to assess discovery rates of the weir box and collection flumes. However, the multistate model allowed us to provide unbiased estimates of the percentage of tagged fish that were collected through each route, and these data showed that few fish were collected through the weir box. Overall, the fish collection system performed reasonably well in collecting juvenile steelhead and coho salmon during the 2013 collection season. Fish collection efficiency estimates from the Washington Department of Fish and Wildlife showed that steelhead collection efficiency was slightly higher than the 10-year average (46 percent compared to 42 percent), whereas coho salmon collection efficiency was more than twice as high as the 10-year average (63 percent compared to 30 percent). However, the performance of the weir box was poor because most fish were collected through the collection flumes.

Washington↗
USGS2022

Extending the Stream Salmonid Simulator to accommodate the life history of coho salmon (Oncorhynchus kisutch) in the Klamath River Basin, Northern California

In this report, we apply the stream salmonid simulator (S3) to coho salmon ( Oncorhynchus kisutch ) in the Klamath River Basin by extending the original model to account for life history and disease dynamics specific to coho salmon. This version of S3 includes tracking of three separate life-history strategies representing the different time periods and ages at which fish leave natal tributaries such as the Scott and Shasta Rivers (age-0 spring, age-0 fall, or age-1 smolt). Once fish leave their natal tributaries and enter the Klamath River, the deterministic life-stage-structured population model simulates daily growth, movement, and survival. We extend the model to include non-natal tributary dynamics, where spring age-0 fish entry to non-natal tributaries is simulated based on environmental conditions in the main-stem Klamath River. Fish that use non-natal tributaries then reenter the Klamath River during the winter or spring as smolts and actively migrate downstream. We also consider the life history strategy where fish rear in natal tributaries and enter the Klamath River as age-1 smolts. In addition to simulating different life history pathways that coho salmon may take, we model disease dynamics, incorporating new information on Ceratonova shasta related infection and mortality. We incorporate competitive interactions between juvenile coho and Chinook salmon ( Oncorhynchus tshawytscha ) by simulating density-dependent movement dynamics in response to Chinook salmon abundance. Model simulations suggest that total abundance and survival to the ocean differed between life-history strategies. In general, spring age-0 fish that leave their natal tributaries in their first spring had lower survival compared with fish that remained in natal tributaries and out-migrated later. Spring age-0 fish also had higher disease related mortality, owing to their residence in the main-stem Klamath River overlapping with periods of elevated C. shasta spore concentrations. Age-0 fish leaving their natal tributaries in the fall had near-zero disease related mortality. Most non-natal tributary use occurred at upstream tributary locations and was variable between the brood years depending on passage timing and environmental conditions. The inclusion of Chinook salmon in simulations resulted in decreased abundance and survival of Coho salmon reaching the ocean. In addition, we developed an R package to facilitate use of and continued development of S3 as a tool to guide management of juvenile salmonid populations.

California↗
USGS2022

The thermal landscape of the Willamette River—Patterns and controls on stream temperature and implications for flow management and cold-water salmonids

Water temperature is a primary control on the health, diversity, abundance, and distribution of aquatic species, but thermal degradation resulting from anthropogenic influences on rivers is a challenge to threatened species worldwide. In the Willamette River Basin, northwestern Oregon, spring-run Chinook salmon ( Oncorhynchus tshawytscha ) and winter-run steelhead ( O. mykiss ) are formerly abundant cold-water-adapted species that are now protected under the Endangered Species Act. Among the challenges to the health of cold-water salmonids in the Willamette River Basin, disruptions in the seasonal patterns of stream temperature imposed by 13 large, multipurpose dams on tributaries to the Willamette River, as well as temperatures routinely in excess of regulatory limits in the Willamette River Basin, are contributing factors. To better understand controls on stream temperature, the sensitivity of stream temperature to flow augmentation as a management tool for suppressing high temperatures, and the implications for threatened salmonids, this study used a two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) to investigate spatial and temporal patterns of stream temperature in the Willamette River Basin. This study focused on the upper 160.4 river miles of the Willamette River from the confluence of the Middle Fork and Coast Fork Willamette Rivers (river mile 187.2) to Willamette Falls (river mile 26.8), three representative climate years (2011, a cool and wet year; 2015, an extremely hot and dry year; and 2016, a moderately hot and dry year), and a series of flow-augmentation scenarios. Model results show that the Willamette River upstream from Willamette Falls is divisible into four characteristic “thermal reaches” with similar thermal patterns, depending on tributary input, warming rate, and the timing of thermal response. In general, the Willamette River warms downstream during spring and summer, but patterns are complex, influenced by tributary inflows, and seasonally variable. Except in cool wet years (as illustrated by 2011), modeling suggests that adversely warm conditions for spring-run Chinook salmon are extensive from June or July through August. The thermal influence of flow augmentation from dam storage on four tributaries with U.S. Army Corps of Engineers dams varies spatially along the Willamette River, seasonally, and in magnitude, depending on a range of factors like distance from the Willamette River, the temperature of dam outflow, and the thermal template of tributary reaches controlling stream temperature adjustment to environmental heat fluxes. Modeling suggests that targeted flow management (via augmentation from dam storage) can reduce the extent and duration of thermally stressful conditions for Chinook salmon for short periods, but modeling suggests that flow augmentation is limited in its ability to fundamentally alter the “thermal landscape” (the entire range of temperature variation in a river system over space and time) of the Willamette River. While this research provides general insights into the thermal landscape of the Willamette River and its sensitivity to flow management, additional investigation into the thermal landscape of tributaries downstream from U.S. Army Corps of Engineers dams, as well as the thermal management of reservoirs, storage availability, and dam outflows, would be necessary to target specific management actions for supporting specified rearing or migration conditions for spring-run Chinook salmon and other cold-water-adapted species in the Willamette River Basin.

Oregon↗
USGS2014

Demographics of piscivorous colonial waterbirds and management implications for ESA-listed salmonids on the Columbia Plateau

We investigated colony size, productivity, and limiting factors for five piscivorous waterbird species nesting at 18 locations on the Columbia Plateau (Washington) during 2004–2010 with emphasis on species with a history of salmonid ( Oncorhynchus spp.) depredation. Numbers of nesting Caspian terns ( Hydroprogne caspia ) and double-crested cormorants ( Phalacrocorax auritus ) were stable at about 700–1,000 breeding pairs at five colonies and about 1,200–1,500 breeding pairs at four colonies, respectively. Numbers of American white pelicans ( Pelecanus erythrorhynchos ) increased at Badger Island, the sole breeding colony for the species on the Columbia Plateau, from about 900 individuals in 2007 to over 2,000 individuals in 2010. Overall numbers of breeding California gulls ( Larus californicus ) and ring-billed gulls ( L. delawarensis ) declined during the study, mostly because of the abandonment of a large colony in the mid-Columbia River. Three gull colonies below the confluence of the Snake and Columbia rivers increased substantially, however. Factors that may limit colony size and productivity for piscivorous waterbirds nesting on the Columbia Plateau included availability of suitable nesting habitat, interspecific competition for nest sites, predation, gull kleptoparasitism, food availability, and human disturbance. Based on observed population trends alone, there is little reason to project increased impacts to juvenile salmonid survival from tern and cormorant populations. Additional monitoring and evaluation may be warranted to assess future impacts of the growing Badger Island American white pelican colony and those gull colonies located near mainstem dams or associated with Caspian tern colonies where kleptoparasitism is common.

Columbia Plateau↗
USGS2012

A simple method for in situ monitoring of water temperature in substrates used by spawning salmonids

Interstitial water temperature within spawning habitats of salmonids may differ from surface-water temperature depending on intragravel flow paths, geomorphic setting, or presence of groundwater. Because survival and developmental timing of salmon are partly controlled by temperature, monitoring temperature within gravels used by spawning salmonids is required to adequately describe the environment experienced by incubating eggs and embryos. Here we describe a simple method of deploying electronic data loggers within gravel substrates with minimal alteration of the natural gravel structure and composition. Using data collected in spawning sites used by summer and fall chum salmon Oncorhynchus keta from two streams within the Yukon River watershed, we compare contrasting thermal regimes to demonstrate the utility of this method.

Journal of Fish and Wildlife Management↗
USGS2010

Non-native salmonids affect amphibian occupancy at multiple spatial scales

Aim The introduction of non-native species into aquatic environments has been linked with local extinctions and altered distributions of native species. We investigated the effect of non-native salmonids on the occupancy of two native amphibians, the long-toed salamander ( Ambystoma macrodactylum ) and Columbia spotted frog ( Rana luteiventris ), across three spatial scales: water bodies, small catchments and large catchments. Location Mountain lakes at ≥ 1500 m elevation were surveyed across the northern Rocky Mountains, USA. Methods We surveyed 2267 water bodies for amphibian occupancy (based on evidence of reproduction) and fish presence between 1986 and 2002 and modelled the probability of amphibian occupancy at each spatial scale in relation to habitat availability and quality and fish presence. Results After accounting for habitat features, we estimated that A. macrodactylum was 2.3 times more likely to breed in fishless water bodies than in water bodies with fish. Ambystoma macrodactylum also was more likely to occupy small catchments where none of the water bodies contained fish than in catchments where at least one water body contained fish. However, the probability of salamander occupancy in small catchments was also influenced by habitat availability (i.e. the number of water bodies within a catchment) and suitability of remaining fishless water bodies. We found no relationship between fish presence and salamander occupancy at the large-catchment scale, probably because of increased habitat availability. In contrast to A. macrodactylum , we found no relationship between fish presence and R. luteiventris occupancy at any scale. Main conclusions Our results suggest that the negative effects of non-native salmonids can extend beyond the boundaries of individual water bodies and increase A. macrodactylum extinction risk at landscape scales. We suspect that niche overlap between non-native fish and A. macrodactylum at higher elevations in the northern Rocky Mountains may lead to extinction in catchments with limited suitable habitat.

Northern Rocky Mountains↗
USGS1982

Freshwater aspects of anadromous salmonid enhancement

Freshwater enhancement of anadromous salmonid populations has been practiced in the United States and Canada since the late 1800's. Reduction of natural spawning habitat and increasing fishing pressure make artificial enhancement a possible alternative to declining populations. Enhancement of anadromous salmonids involved improvement of the natural environment and reducing natural mortality. Methods of enhancement include fishways, spawning and rearing channels, stream rehabilitation, lake fertilization, environmental management, and artificial propagation techniques. Five Pacific salmon species and steelhead trout are commonly enhanced, primarily in watershed entering the Pacific Ocean and Great Lakes. Enhancement efforts contribute heavily to a commercial and sport industry realizing over $1.5 billion.

NOAA Technical Report NMFS Circular↗
USGS2010

Juvenile Salmonid survival, passage, and egress at McNary Dam during tests of temporary spillway weirs, 2009

We evaluated behavior, passage, and survival of juvenile salmonids at McNary Dam in relation to the temporary spillway weirs (TSWs) using acoustic telemetry during 2009. The TSWs were located in spill bays 4 and 20 during spring and in spill bays 19 and 20 during summer. Our objectives were to assess the performance of the TSWs as a fish passage alternative. We also examined how tailrace conditions might have influenced fish survival by releasing drift buoys (drogues). The TSWs proved to be a relatively effective way to pass juvenile salmonids at McNary Dam (Summary Tables 1.1, 1.2, and 1.3), as was the case in 2007 and 2008. The TSWs passed about 14% of yearling Chinook salmon and 34% of juvenile steelhead with only 5-10% of total project discharge flowing through the TSWs. The TSWs and adjacent spill bays 16-18 passed 27% of subyearling Chinook salmon in the summer with 6-16% of total project discharge flowing through the TSWs. Based on the number of fish passing per the proportion of water flowing through the spillway (i.e., passage effectiveness), the TSWs were the most effective passage route. Passage effectiveness for fish passing through both TSW structures was 2.0 for yearling Chinook salmon, 5.2 for juvenile steelhead, and 2.7 subyearling Chinook salmon for TSW 20 alone. Higher passage of juvenile steelhead through the TSWs could have resulted from juvenile steelhead being more surface-oriented during migration (Plumb et al. 2004; Beeman et al. 2007; Beeman and Maule 2006). Based on passage performance and effectiveness metrics, TSW 4, located on the north end of the spillway, did not perform as well as TSW 20, located on the south end of the spillway. Passage proportions for TSW 4 were at least half that of the levels observed for TSW 20 for both yearling Chinook salmon and juvenile steelhead. This difference may be attributed to TSW location or other variables such as dam operations. Regardless of which TSW was used by fish passing the dam, survival through both TSWs was high (> 0.98 for paired-release dam survival) for yearling Chinook salmon and juvenile steelhead.

Oregon, Washington↗
USGS2012

A fine-scale assessment of using barriers to conserve native stream salmonids: a case study in Akokala Creek, Glacier National Park, USA

Biologists are often faced with the difficult decision in managing native salmonids of where and when to install barriers as a conservation action to prevent upstream invasion of nonnative fishes. However, fine-scale approaches to assess long-term persistence of populations within streams and watersheds chosen for isolation management are often lacking. We employed a spatially-explicit approach to evaluate stream habitat conditions, relative abundance, and genetic diversity of native westslope cutthroat trout (Oncorhynchus clarkii lewisi) within the Akokala Creek watershed in Glacier National Park- a population threatened by introgressive hybridization with nonnative rainbow trout (O. mykiss) from nearby sources. The systematic survey of 24 stream reaches showed broad overlap in fish population and suitable habitat characteristics among reaches and no natural barriers to fish migration were found. Analysis of population structure using 16 microsatellite loci showed modest amounts of genetic diversity among reaches, and that fish from Long Bow Creek were the only moderately distinct genetic group. We then used this information to assess the potential impacts of three barrier placement scenarios on long-term population persistence and genetic diversity. The two barrier placement scenarios in headwater areas generally failed to meet general persistence criteria for minimum population size (2,500 individuals, Ne = 500), maintenance of long-term genetic diversity (He), and no population subdivision. Conversely, placing a barrier near the stream mouth and selectively passing non-hybridized, migratory spawners entering Akokala Creek met all persistence criteria and may offer the best option to conserve native trout populations and life history diversity. Systematic, fine-scale stream habitat, fish distribution, and genetic assessments in streams chosen for barrier installation are needed in conjunction with broader scale assessments to understand the potential impacts of using barriers for conservation of native salmonid populations threatened by nonnative fish invasions.

Open Fish Science Journal↗
USGS2007

Weirs: Counting and sampling adult salmonids in streams and rivers

Weirs—which function as porous barriers built across stream—have long been used to capture migrating fish in flowing waters. For example, the Netsilik peoples of northern Canada used V-shaped weirs constructed of river rocks gathered onsite to capture migrating Arctic char Salvelinus alpinus (Balikci 1970). Similarly, fences constructed of stakes and a latticework of willow branches or staves were used by Native Americans to capture migrating salmon in streams along the West Coast of North America (Stewart 1994). In modern times, weirs have also been used in terminal fisheries and to capture brood fish for use in fish culture. Weirs have been used to gather data on age structure, condition, sex ratio, spawning escapement, abundance, and migratory patterns of fish in streams. One of the critical elements of fisheries management and stock assessment of salmonids is a count of adult fish returning to spawn. Weirs are frequently used to capture or count fish to determine status and trends of populations or direct inseason management of fisheries; generally, weirs are the standard against which other techniques are measured. To evaluate fishery management actions, the number of fish escaping to spawn is often compared to river-specific target spawning requirements (O’Connell and Dempson 1995). A critical factor in these analyses is the determination of total run size (O’Connell 2003). O’Connell compared methods of run-size estimation against absolute counts from a rigid weir and concluded that, given the uncertainty of estimators, the absolute counts obtained at the weir wer significantly better than modeled estimates, which deviated as much as 50–60% from actual counts. The use of weirs is generally restricted to streams and small rivers because of construction expense, formation of navigation barriers, and the tendency of weirs to clog with debris, which can cause flooding and collapse of the structure (Hubert 1996). When feasible, however, weirs are generally regarded as the most accurate technique available to quantify escapement as the result is supposedly an absolute count (Cousens et al. 1982). Weirs also provide the opportunity to capture fish for observation and sampling of biological characteristics and tissues; they may also serve as recapture sites for basin-wide, mark–recapture population estimates. Temporary weirs are useful in monitoring wild populations of salmonids as well as for capturing broodstock for artificial propagation.

Book chapter↗
USGS2026

Toxicity of 6PPD alternatives to salmonid cell lines

Stormwater runoff in urban areas introduces numerous anthropogenic chemicals into surrounding aquatic environments. One such chemical is 6PPD ( N -(1,3-Dimethylbutyl)- N ’-phenyl- p- phenylenediamine), the primary antidegradant responsible for protecting tire rubber from ozone-induced degradation and cracking. When exposed to ozone on the road surface 6PPD is transformed into the toxic transformation product 6PPD-quinone (6PPDQ). This compound is highly lethal to coho salmon ( O ncorhynchus kisutch ), and 24 hour 50% lethal concentrations (LC 50 ; 41-95 ng/L) are frequently detected in urban streams during stormwater runoff events 1-5 . The highest stream concentrations of 6PPDQ and most extensive coho salmon mortality occur in high-traffic urban areas, where tire wear particles accumulate due to the frequent braking and acceleration of cars 6 . In the Seattle area, some coho salmon-bearing streams can lose over 90% of returning females prior to spawning due to 6PPDQ-containing runoff 7 . Prespawn loss of this magnitude could result in the extinction of some urban spawning populations 8 . Importantly, the lethal effects of 6PPDQ have been observed in several other salmonid species, indicating that its impact may threaten fish health for urban aquatic environments globally 9-11 . The ubiquity of 6PPD in automobile tires, high toxicity of the transformation product 6PPDQ, and prevalence of 6PPD and 6PPDQ in environmental matrices has spurred investigations into alternative rubber antiozonants to replace 6PPD that retain tire performance while reducing ecological harm. A technical memorandum provided to the legislature by the Washington State Department of Ecology summarized a list of potential 6PPD alternatives requiring further study, including several structurally similar p-phenylenediamines (PPDs) 12 . However, the structural similarity of other PPDs to 6PPD and their known production of quinone transformation products 13 raises concerns that they may elicit similar toxic effects as 6PPDQ. Currently, investigations into the toxicity of proposed PPD alternatives or their ozonated transformation products in coho salmon are limited, representing a significant data gap in evaluating whether they offer improved environmental safety over 6PPD. This project investigated the toxicity of proposed alternative rubber antiozonants in vitro using immortalized cell lines derived from three salmonid species with known differences in sensitivity to 6PPDQ (coho salmon, Chinook salmon ( O. tshawytscha ), rainbow trout ( O. mykiss )) 1 . These immortalized cell lines replicate toxic responses observed in in vivo studies, while enabling higher-throughput testing and reducing the need for animal use and other resource-intensive procedures. The antiozonants and their transformation products selected for testing were chosen based on multiple criteria, including their inclusion in the Ecology technical memorandum, structural substitutions (e.g., branched/cyclic alkyl vs aryl substitutions), commercial availability, and input from the Washington State Department of Ecology and other industry experts.

Report↗
USGS2012

Incorporating spatial context into the analysis of salmonid habitat relations

In this response to the chapter by Lapointe (this volume), we discuss the question of why it is so difficult to predict salmonid-habitat relations in gravel-bed rivers and streams. We acknowledge that this cannot be an exhaustive treatment of the subject and, thus, identify what we believe are several key issues that demonstrate the necessity of incorporating spatial context into the analysis of fish-habitat data. Our emphasis is on spatial context (i.e., scale and location), but it is important to note that the same principles may be applied with some modification to temporal context, which is beyond the scope of this chapter.

Oregon↗
USGS2024

Spatial and temporal variability of movements among sympatric salmonids in an unfragmented inland watershed

Objective Our aim was to determine the movement patterns of three abundant salmonids—Brown Trout Salmo trutta , Mountain Whitefish Prosopium williamsoni , and Rainbow Trout Oncorhynchus mykiss —in the Smith River watershed of Montana. Methods We tagged 7172 fish with passive integrated transponder (PIT) tags, monitored their movements past 15 stationary PIT arrays over 4 years, and located tagged fish between arrays by conducting mobile surveys. Result Movement patterns varied seasonally, among species, and among locations. Movement was greatest in the middle portion of the watershed, which included a pristine main‐stem canyon and lower reaches of major tributaries. Fish rarely left the canyon, but movement into the canyon from other regions was common. Mountain Whitefish were most likely to move, and Brown Trout were least likely to move. Most fish travelled less than 10 km, but some fish travelled over 100 km. Distinct movement patterns were not evident; rather, a continuous spectrum of movement behaviors was apparent. Movements by Mountain Whitefish and Rainbow Trout increased during their spawning periods. Movements peaked when mean daily water temperatures were between 11.3 and 17.1°C. Conclusion Movements were diverse and probably contributed to metapopulation dynamics, population resiliency, and species diversity. Fish movements along stream networks connect populations across diverse landscapes, and therefore, protecting and restoring stream connectivity along inland streams such as the Smith River is critical to maintaining productive fish assemblages.

Montana↗
USGS1972

Fish rhabdoviruses: Morphology and ultrastructure of North American salmonid isolates

The morphology and ultrastructure of three North American salmonid pathogens, Oregon sockeye salmon, chinook salmon and infectious hematopoietic necrosis viruses, were examined by thin sectioning and negative staining after growth in fathead minnow cells at 10 ° C. The viruses matured at the plasma membrane of these cells. They were approximately 170 nm in length, 70 nm in width and had internal striations with a periodicity of 5.5nm. They were rounded on one end and planar on the other ( i.e. , bullet shaped). By morphological criteria, these viruses are rhabdoviruses with dimensions and ultrastructural features similar to vesicular stomatitis virus.

Archiv Fur Die Gesamte Virusforschung↗
USGS2018

A comparative evaluation of crowding stress on muscle HSP90 and myostatin expression in salmonids

Stress is a major factor that contributes to poor production and animal welfare concerns in aquaculture. As such, a thorough understanding of mechanisms involved in the stress response is imperative to developing strategies to mitigate the negative side effects of stressors, including the impact of high stocking densities on growth. The purpose of this study was to determine how the muscle growth inhibitor, myostatin , and the stress-responsive gene HSP90 are regulated in response to crowding stress in rainbow trout ( Oncorhynchus mykiss ), cutthroat trout ( Oncorhynchus clarki ), brook trout ( Salvelinus fontinalis ), and Atlantic salmon ( Salmo salar ). All species exhibited higher cortisol and glucose levels following the handling stress, indicating physiological response to the treatment. Additionally, all species, except rainbow trout, exhibited higher HSP90 levels in muscle after a 48 h crowding stress. Crowding stress resulted in a decrease of myostatin-1a in brook trout white muscle but not red muscle, while, myostatin-1a and -2a levels increased in white muscle and myostatin-1b levels increased in red muscle in Atlantic salmon. In rainbow trout, no significant changes were detected in either muscle type, but myostatin-1a was upregulated in both white and red skeletal muscle in the closely related cutthroat trout. The variation in response to crowding suggests a complex and species-specific interaction between stress and the muscle gene regulation in these salmonids. Only Atlantic salmon and cutthroat trout exhibited increased muscle myostatin transcription, and also exhibited the largest increase in circulating glucose in response to crowding. These results suggest that species-specific farming practices should be carefully examined in order to optimize low stress culture conditions.

Aquaculture↗
USGS2015

Characterizing the distribution of an endangered salmonid using environmental DNA analysis

Determining species distributions accurately is crucial to developing conservation and management strategies for imperiled species, but a challenging task for small populations. We evaluated the efficacy of environmental DNA (eDNA) analysis for improving detection and thus potentially refining the known distribution of Chinook salmon ( Oncorhynchus tshawytscha ) in the Methow and Okanogan Subbasins of the Upper Columbia River, which span the border between Washington, USA and British Columbia, Canada. We developed an assay to target a 90 base pair sequence of Chinook DNA and used quantitative polymerase chain reaction (qPCR) to quantify the amount of Chinook eDNA in triplicate 1-L water samples collected at 48 stream locations in June and again in August 2012. The overall probability of detecting Chinook with our eDNA method in areas within the known distribution was 0.77 (±0.05 SE). Detection probability was lower in June (0.62, ±0.08 SE) during high flows and at the beginning of spring Chinook migration than during base flows in August (0.93, ±0.04 SE). In the Methow subbasin, mean eDNA concentration was higher in August compared to June, especially in smaller tributaries, probably resulting from the arrival of spring Chinook adults, reduced discharge, or both. Chinook eDNA concentrations did not appear to change in the Okanogan subbasin from June to August. Contrary to our expectations about downstream eDNA accumulation, Chinook eDNA did not decrease in concentration in upstream reaches (0–120 km). Further examination of factors influencing spatial distribution of eDNA in lotic systems may allow for greater inference of local population densities along stream networks or watersheds. These results demonstrate the potential effectiveness of eDNA detection methods for determining landscape-level distribution of anadromous salmonids in large river systems.

British Columbia, Washington↗
USGS2023

Simulating the migration dynamics of juvenile salmonids through rivers and estuaries using a hydrodynamically driven enhanced particle tracking model

Juvenile salmonids migrate hundreds of kilometers from their natal streams to mature in the ocean. Throughout this migration, they respond to environmental cues such as local water velocities and other stimuli to direct and modulate their movements, often through heavily modified riverine and estuarine habitats. Management strategies in an uncertain future of climate change and altered land use regimes depend heavily on being able to reliably predict their ocean entry timings, route use, and survival rates through rivers and estuaries. We developed a spatially-explicit agent-based model of fish movement in response to hydrodynamic flows that uses movement dynamics gleaned from multi-dimensional tracking datasets of acoustically tagged juveniles moving through an urbanized, branched tidal estuary. We demonstrate how such models can be calibrated, and we apply it to the Sacramento-San Joaquin Delta in Central California. The quality of the out-of-sample validation of the model to predict juvenile salmon survival and route selection indicates that the model is versatile and flexible enough to be used in novel hydroclimatological conditions.

California↗
USGS2017

Accurate aging of juvenile salmonids using fork lengths

Juvenile salmon life history strategies, survival, and habitat interactions may vary by age cohort. However, aging individual juvenile fish using scale reading is time consuming and can be error prone. Fork length data are routinely measured while sampling juvenile salmonids. We explore the performance of aging juvenile fish based solely on fork length data, using finite Gaussian mixture models to describe multimodal size distributions and estimate optimal age-discriminating length thresholds. Fork length-based ages are compared against a validation set of juvenile coho salmon, Oncorynchus kisutch , aged by scales. Results for juvenile coho salmon indicate greater than 95% accuracy can be achieved by aging fish using length thresholds estimated from mixture models. Highest accuracy is achieved when aged fish are compared to length thresholds generated from samples from the same drainage, time of year, and habitat type (lentic versus lotic), although relatively high aging accuracy can still be achieved when thresholds are extrapolated to fish from populations in different years or drainages. Fork length-based aging thresholds are applicable for taxa for which multiple age cohorts coexist sympatrically. Where applicable, the method of aging individual fish is relatively quick to implement and can avoid ager interpretation bias common in scale-based aging.

Fisheries Research↗